It seems to be improving but I am still surprised at how many in our profession, including inspectors, who have no concept of "withstand current" and "AIC". I used to reject installations over that ,and my supervisor complained that out of 54 inspectors there were 3 of us that seemingly addressed the issue.
Feeding Chiller Module
- Thread starter Tainted
- Start date
So the sales person I contacted said no and that he's not an engineer obviously, I told him if I can speak with one of the engineers at the chiller company and waiting to hear back...
synchro
Senior Member
- Location
- Chicago, IL
- Occupation
- EE
What secondary voltage on the transformer did you use for these calculations?
Knightryder12
Senior Member
- Location
- Clearwater, FL - USA
- Occupation
- Sr. Electrical Designer/Project Manager
What manufacturer is this? Our mechanical guys work with Trane, Daikin, etc and they all offer higher than 10K AIC.
At this point it's about ethics, why would he complain for doing your job?
Our unwritten prime responsibility was "don't generate calls to the office"
Addressing fault current situations was new to some ECs and GCs so there 1st reaction was to complain to the inspector's supervisor ie: an unwanted phone call,.
No doubt you have heard the "we install these all over and no one has ever asked for such a thing"......
Knightryder12
Senior Member
- Location
- Clearwater, FL - USA
- Occupation
- Sr. Electrical Designer/Project Manager
Never heard of these guys down here in the south. But it still surprises me that cannot offer anything higher than 10K.
The sales guy is not even an engineer so I don't even know if he understands what I'm talking about with SCCR. Hopefully when I speak with manufacturer they will give me something higher than 10kA
Let's play a little devils advocate... I'm kind of wondering though has there ever been an incident where an HVAC equipment SCCR was undersized and it created a catastrophic failure? I'm sure it can happen but I would assume it being extremely rareOur unwritten prime responsibility was "don't generate calls to the office"
Addressing fault current situations was new to some ECs and GCs so there 1st reaction was to complain to the inspector's supervisor ie: an unwanted phone call,.
No doubt you have heard the "we install these all over and no one has ever asked for such a thing"......
synchro
Senior Member
- Location
- Chicago, IL
- Occupation
- EE
When you speak with the manufacturer, perhaps you could ask them if you could provide individual overcurrent protection for each of the 8 chiller modules. If they push back then you could mention that their installation manual says it's mandatory for a circuit breaker to be "installed as near as possible to the appliance", and that using individual breakers would allow this to happen.
But it will be protected with fuses, hence they give us recommended fuse size... why do we need a circuit breaker?
Last edited:
synchro
Senior Member
- Location
- Chicago, IL
- Occupation
- EE
At least in the manual that I found, it says this on page 17 under the heading of "it is mandatory: ".
I don't have any idea if this is the most up-to-date manual.
I found it... but I edited my question
it will be protected with fuses, hence they give us recommended fuse size... why do we need a circuit breaker?
synchro
Senior Member
- Location
- Chicago, IL
- Occupation
- EE
I'm not blaming you lol. It just makes no sense how they written it. Furthermore, there is an internal switch that cuts off power to the compressors.Don't blame me, I'm just the messenger.
synchro
Senior Member
- Location
- Chicago, IL
- Occupation
- EE
I think it's just another reason why you need to get info from real engineers and not sales people.
And they expect a circuit breaker to be as close as possible to the unit while keeping the fault current below 10kA? Are you freaking kidding me!?!
Maybe not as a protective device but as a disconnect for safety purposes. That is a provision in the OSHA, a disconnect that is located within line of sight from the equipment. One project of mine (80-ton RTUs) have circuit breakers near them (all eight of them).
The unit already has a built in disconnect so I don't know what the heck they're talking about in that manual. See below circle in blue
